1. Field of the Invention
The invention relates to spiral wire binder applying machines of the type in which the forming and insertion of the spiral wire is closely followed by cutting and crimping or inwardly bending the coil ends.
2. Description of the Prior Art
In the past it has been conventional to feed the spiral wire binder through the aligned apertures in the group of sheets which forms the book and, upon a signal responsive to the full insertion of the binder, stopping the feed and simultaneously actuating the cutting and crimping mechanism which severs the coil ends and bends them inwardly toward each other.
During the forming and inserting operation it is possible to store energy in the coil because of the driving force in the coiling tool and friction between the coil and the holes through which they are being driven. This energy storage occurs particularly in applications where the diameter of the coil is relatively large, perhaps 20 mm or larger, and in coil binding machines having relatively high rotational mandrel speeds. The amount of energy stored in the coil could be referred to as a wind up effect, and is greatest at the moment the coiling operation ceases. At this time the coil will tend to release this energy by unwinding. The time required to release this energy is perhaps up to one second in range depending upon the diameter and length of the coil.
Previously, the spiral wire applying machines did not have means for allowing energy relief time for the coil before the cutting cycle was actuated. This caused the coil to unwind after the ends were cut and crimped. This in turn created an undesirable effect on the finished product since the inwardly bent ends were not aligned and this could cause distortion of the book itself and possibly interfere with full opening movement. Thus, the effect particularly for larger coil diameters was both unsatisfactory appearance and malfunction.